One thing I've though would be a cool addition for this game, and something that you frequently see in zombie flicks, is the ability to barricade doors (and maybe windows) in buildings. This would prevent zombies and other players from opening a door. This barricade would, however, have a breaking point. With enough attacks on it, it would wear down and break, allowing entry. This way, players would obviously have to use some kind of weapon to destroy the barricade, thus making noise and potentially aggro'ing nearby zombies. So breaking and entering would be a calculated risk. It may also be cool to be able to have doors that you can lock, and potentially have keys for. The way this might work is that sure, you could shoot out a door's lock and enter, but then the lock on that door would not work, and there could also potentially be a new mechanic added to allow you to repair or replace broken locks. I just really like the idea of being able to fortify and hold up in a house or large building, but have it be at a cost to keep it secure, and also have it not be impenetrable. I think these mechanics could definitely influence cooperation in the game. It could also create clan/territory wars on servers, and make for some very interesting encounters. Do you create a camp out in the middle of nowhere so your stuff is safe? Or do you establish a very strong home base in the town, servicing passer-bys, granting them food and/or protection from zombies/others, but for a price. Or, you know, you could just be a militant group of bandits hell-bent on controlling all of Cherno/Elektro. Any thoughts?